A pleiotropic variant in DNAJB4 is associated with multiple myeloma risk.

Pleiotropy, which consists of a single gene or allelic variant affecting multiple unrelated traits, is common across cancers, with evidence for genome-wide significant loci shared across cancer and noncancer traits. This feature is particularly relevant in multiple myeloma (MM) because several susceptibility loci that have been identified to date are pleiotropic. Therefore, the aim of this study was to identify novel pleiotropic variants involved in MM risk using 28 684 independent single nucleotide polymorphisms (SNPs) from GWAS Catalog that reached a significant association (P < 5 × 10-8 ) with their respective trait. The selected SNPs were analyzed in 2434 MM cases and 3446 controls from the International Lymphoma Epidemiology Consortium (InterLymph). The 10 SNPs showing the strongest associations with MM risk in InterLymph were selected for replication in an independent set of 1955 MM cases and 1549 controls from the International Multiple Myeloma rESEarch (IMMEnSE) consortium and 418 MM cases and 147 282 controls from the FinnGen project. The combined analysis of the three studies identified an association between DNAJB4-rs34517439-A and an increased risk of developing MM (OR = 1.22, 95%CI 1.13-1.32, P = 4.81 × 10-7 ). rs34517439-A is associated with a modified expression of the FUBP1 gene, which encodes a multifunctional DNA and RNA-binding protein that it was observed to influence the regulation of various genes involved in cell cycle regulation, among which various oncogenes and oncosuppressors. In conclusion, with a pleiotropic scan approach we identified DNAJB4-rs34517439 as a potentially novel MM risk locus.

Harnessing the Immune System to Fight Multiple Myeloma.

Multiple myeloma (MM) is a heterogeneous plasma cell malignancy differing substantially in clinical behavior, prognosis, and response to treatment. With the advent of novel therapies, many patients achieve long-lasting remissions, but some experience aggressive and treatment refractory relapses. So far, MM is considered incurable. Myeloma pathogenesis can broadly be explained by two interacting mechanisms, intraclonal evolution of cancer cells and development of an immunosuppressive tumor microenvironment. Failures in isotype class switching and somatic hypermutations result in the neoplastic transformation typical of MM and other B cell malignancies. Interestingly, although genetic alterations occur and evolve over time, they are also present in premalignant stages, which never progress to MM, suggesting that genetic mutations are necessary but not sufficient for myeloma transformation. Changes in composition and function of the immune cells are associated with loss of effective immune surveillance, which might represent another mechanism driving malignant transformation. During the last decade, the traditional view on myeloma treatment has changed dramatically. It is increasingly evident that treatment strategies solely based on targeting intrinsic properties of myeloma cells are insufficient. Lately, approaches that redirect the cells of the otherwise suppressed immune system to take control over myeloma have emerged. Evidence of utility of this principle was initially established by the observation of the graft-versus-myeloma effect in allogeneic stem cell-transplanted patients. A variety of new strategies to harness both innate and antigen-specific immunity against MM have recently been developed and intensively tested in clinical trials. This review aims to give readers a basic understanding of how the immune system can be engaged to treat MM, to summarize the main immunotherapeutic modalities, their current role in clinical care, and future prospects.

Identification of a clinical signature predictive of differentiation fate of human bone marrow stromal cells.

BACKGROUND: Transplantation of human bone marrow stromal cells (hBMSCs) is a promising therapy for bone regeneration due to their ability to differentiate into bone forming osteoblastic cells. However, transplanted hBMSCs exhibit variable capacity for bone formation resulting in inconsistent clinical outcome. The aim of the study was to identify a set of donor- and cell-related characteristics that detect hBMSCs with optimal osteoblastic differentiation capacity. METHODS: We collected hBMSCs from 58 patients undergoing surgery for bone fracture. Clinical profile of the donors and in vitro characteristics of cultured hBMSCs were included in uni- and multivariable analysis to determine their predictive value for osteoblastic versus adipocytic differentiation capacity assessed by quantification of mineralized matrix and mature adipocyte formation, respectively. RESULTS: We identified a signature that explained > 50% of variation in osteoblastic differentiation outcome which included the following positive predictors: donor sex (male), absence of osteoporosis diagnosis, intake of vitamin D supplements, higher fraction of CD146+, and alkaline phosphate (ALP+) cells. With the exception of vitamin D and ALP+ cells, these variables were also negative predictors of adipocytic differentiation. CONCLUSIONS: Using a combination of clinical and cellular criteria, it is possible to predict differentiation outcome of hBMSCs. This signature may be helpful in selecting donor cells in clinical trials of bone regeneration.

Fibrocytes in early and long-standing rheumatoid arthritis: a 6-month trial with repeated synovial biopsy, imaging and lung function test.

OBJECTIVES: To correlate the level of fibrocytes in peripheral blood, synovial tissue and in vitro culture in rheumatoid arthritis (RA) with changes in disease activity, imaging and pulmonary function. METHODS: Twenty patients with early RA (ERA) and 20 patients with long-standing RA (LRA) were enrolled in a 6-month prospective study. Sixteen patients undergoing wrist arthroscopy were healthy controls. Patients with RA underwent pulmonary function tests, ultrasound and synovial ultrasound-guided needle biopsy of the same wrist at baseline and 6 months. Wrist MRI was performed at baseline (all) and 6 months (ERA). Circulating fibrocytes were measured by flow cytometry, in vitro by the number of monocytes that were differentiated to fibrocytes and in synovial biopsies by counting in histological sections. RESULTS: Fibrocytes were primarily located around vessels and in the subintimal area in the synovium. Fibrocyte levels did not decline during the trial despite effective RA treatment. In the ERA group, increased synovitis assessed by ultrasound was moderate and strongly correlated with an increase in circulating and synovial fibrocyte levels, respectively. Increased synovitis assessed by MRI during the trial in the ERA group was moderately correlated with both increased numbers of circulating and cultured fibrocytes. Absolute diffusion capacity level was overall weakly negatively correlated with the level of circulating and synovial fibrocytes. The decline in diffusion capacity during the trial was moderately correlated with increased levels of synovial fibrocytes. CONCLUSION: Our findings suggest that fibrocytes are involved in RA pathogenesis, both in the synovium and the reduction in lung function seen in a part of patients with RA. TRIAL REGISTRATION NUMBER: NCT02652299.

Expression quantitative trait loci of genes predicting outcome are associated with survival of multiple myeloma patients.

Gene expression profiling can be used for predicting survival in multiple myeloma (MM) and identifying patients who will benefit from particular types of therapy. Some germline single nucleotide polymorphisms (SNPs) act as expression quantitative trait loci (eQTLs) showing strong associations with gene expression levels. We performed an association study to test whether eQTLs of genes reported to be associated with prognosis of MM patients are directly associated with measures of adverse outcome. Using the genotype-tissue expression portal, we identified a total of 16 candidate genes with at least one eQTL SNP associated with their expression with P < 10-7 either in EBV-transformed B-lymphocytes or whole blood. We genotyped the resulting 22 SNPs in 1327 MM cases from the International Multiple Myeloma rESEarch (IMMEnSE) consortium and examined their association with overall survival (OS) and progression-free survival (PFS), adjusting for age, sex, country of origin and disease stage. Three polymorphisms in two genes (TBRG4-rs1992292, TBRG4-rs2287535 and ENTPD1-rs2153913) showed associations with OS at P < .05, with the former two also associated with PFS. The associations of two polymorphisms in TBRG4 with OS were replicated in 1277 MM cases from the International Lymphoma Epidemiology (InterLymph) Consortium. A meta-analysis of the data from IMMEnSE and InterLymph (2579 cases) showed that TBRG4-rs1992292 is associated with OS (hazard ratio = 1.14, 95% confidence interval 1.04-1.26, P = .007). In conclusion, we found biologically a plausible association between a SNP in TBRG4 and OS of MM patients.

Emerging Approaches for Regulation and Control of CAR T Cells: A Mini Review.

Chimeric antigen receptor (CAR) T cells have emerged as a promising treatment for patients with advanced B-cell cancers. However, widespread application of the therapy is currently limited by potentially life-threatening toxicities due to a lack of control of the highly potent transfused cells. Researchers have therefore developed several regulatory mechanisms in order to control CAR T cells in vivo. Clinical adoption of these control systems will depend on several factors, including the need for temporal and spatial control, the immunogenicity of the requisite components as well as whether the system allows reversible control or induces permanent elimination. Here we describe currently available and emerging control methods and review their function, advantages, and limitations.

Chimeric Antigen Receptor T Cells Targeting CD79b Show Efficacy in Lymphoma with or without Cotargeting CD19.

PURPOSE: T cells engineered to express a chimeric antigen receptor (CAR) against CD19 have recently been FDA approved for the treatment of relapsed or refractory large B-cell lymphoma. Despite the success and curative potential of CD19 CAR T cells, several reports describing disease relapse due to antigen loss are now emerging. EXPERIMENTAL DESIGN: We developed a novel CAR construct directed against CD79b, a critical receptor for successful B-cell development that remains highly expressed in several subtypes of B-cell lymphoma, including mantle cell lymphoma (MCL). We tested CAR T cells directed against CD79b alone or in combination with CD19 targeting in a single construct, against cell line- and patient-derived xenograft models. RESULTS: We demonstrate CAR79b antigen-specific recognition and cytotoxicity against a panel of cell lines and patient-derived xenograft models of MCL. Importantly, we show that downregulation of CD19 does not influence surface expression of CD79b and that anti-CD79b CAR T cells alone or arranged in a dual-targeting format with a CD19 single-chain variable fragment (scFv) are able to recognize and eliminate CD19+, CD19-, and mixed CD19+/CD19-B-cell lymphoma. CONCLUSIONS: Our findings demonstrate that CAR T cells targeting CD79b alone or in combination have promise for treating and preventing CD19 antigen escape in B-cell lymphomas.

Genetic polymorphisms in genes of class switch recombination and multiple myeloma risk and survival: an IMMEnSE study.

Genetic variants in genes acting during the maturation process of immature B-cell to differentiated plasma cell could influence the risk of developing multiple myeloma (MM). During B-cell maturation, several programmed genetic rearrangements occur to increase the variation of the immunoglobulin chains. Class switch recombination (CSR) is one of the most important among these mechanisms. Germline polymorphisms altering even subtly this process could play a role in the etiology and outcome of MM. We performed an association study of 30 genetic variants in the key CSR genes, using 2632 MM patients and 2848 controls from the International Multiple Myeloma rESEarch (IMMEnSE) consortium, the Heidelberg MM Group and the ESTHER cohort. We found an association between LIG4-rs1555902 and decreased MM risk, which approached statistical significance, as well as significant associations between AICDA-rs3794318 and better outcome. Our results add to our knowledge on the genetic component of MM risk and survival.

The composition of T cell subtypes in duodenal biopsies are altered in coeliac disease patients.

One of the hallmarks of Celiac disease (CD) is intraepithelial lymphocytosis in the small intestine. Until now, investigations to characterize the T cell subpopulations within the epithelial layer have not discriminated between the heterodimeric co-receptor molecule, CD8αß, and the possibly immunoregulatory CD8αα homodimer molecule. Besides TCRαß+ CD4+ cells, no other phenotypes have been shown to be gluten-reactive. Using flow cytometry on lymphocytes from duodenal biopsies, we determined that the number of B cells (CD3- CD19+) and the number of CD3+ CD4- CD8- double-negative (DN) T cells were elevated 6-7 fold in children with CD. We next isolated and quantified intraepithelial lymphocytes (IELs) from biopsies obtained from patients (both children and adults) with CD, potential CD and non-CD controls. Flow cytometric analysis of the duodenal T cell subpopulations was performed including the markers TCRαß, TCRγδ, CD4, CD8α and CD8ß. Proportions of γδ T cells and CD8αß+ cells among IELs were increased in CD patients, whereas proportions of CD4+ CD8αα+ and CD4+ single-positive T cells were decreased. Additionally, two gluten-reactive T cell lines (TCLs) derived from CD biopsies were analyzed for changes in proportions of T cell subsets before and after gluten stimulation. In a proliferation assay, dividing cells were tracked with carboxyfluorescein succinimidyl ester (CFSE), and both αß and γδ T cells proliferated in response to gluten. Changes in duodenal T cell subpopulations in potential CD patients followed the same pattern as for CD patients, but with less pronounced effect.

Evidence of perturbed germinal center dynamics, but preserved antibody diversity, in end-stage renal disease.

INTRODUCTION: End-stage renal disease (ESRD) is associated with increased infectious susceptibility and with reduced vaccine responses consistent with compromised humoral immunity. Whether the compromised humoral immunity is due to reduced antibody diversity (reduced somatic hypermutation [SHM]) or altered germinal center (GC) dynamics is not known. The GC-derived chemokine CXCL13 as well as peripheral T follicular helper cells (pTFH) reflect GC dynamics, but have, similar to SHM, never been characterized in relation to ESRD. METHODS: Serum CXCL 13 was determined by ELISA. PTFH were flow-cytometrically defined as CD4+ CD45RA- CCR7+ CXCR5+ lymphocytes. Apoptotic lymphocyte subsets were in addition annexin V+. SHM was determined, by next-generation sequencing and bioinformatics, as nucleotide mutations within the IgG VH (comprising the important antigen-binding domains of IgG, CDR1, and CDR2). RESULTS: Elevated CXCL13 levels characterized ESRD (n = 19; [median] 90 pg/ml, P < 0.01) (controls, n = 18; 62 pg/ml). ESRD pTFH frequencies (n = 19; 11.6% [of CD4+ memory T cells], P < 0.02*, *Bonferroni corrected) (controls, n = 22; 14.9%) and concentrations (n = 19; 0.03 × 109/L, P < 0.02*) (controls, n = 22; 0.07 × 109/L) were reduced. ESRD pTFH were more apoptotic (n = 9; 25.7%, P = 0.04*) (controls, n = 10; 15.9%). SHM did not discriminate between ESRD (n = 10; 7.4%, P = 0.21) and controls (n = 10; 8.4%). CONCLUSIONS: Elevated CXCL13 levels, reduced pTFH levels, and increased pTFH apoptosis suggest that perturbed GC dynamics, and not reduced antibody diversity, underlie the diminished vaccine responses and the compromised humoral immunity in ESRD. However, largely preserved SHM provides a rationale for pursuing vaccination in relation to ESRD.

Prediction of preeclampsia with angiogenic biomarkers. Results from the prospective Odense Child Cohort.

OBJECTIVE: We aimed to investigate how maternal serum soluble Fms-like kinase 1 (sFlt-1), placental growth factor (PlGF), and sFlt-1/PlGF ratio prospectively associate to preeclampsia (PE) and clinical subtypes. METHODS: In an unselected cohort of 1909 pregnant women, sFlt-1 and PlGF were measured with KRYPTOR assays in gestational weeks (GW) 8-14 and 20-34. Associations to PE were assessed by receiver operating characteristics and logistic regression. RESULTS: Concentrations of sFlt-1, PlGF, and sFlt-1/PlGF in GW20-34 were predictive of PE development, but not in GW8-14. PlGF outperformed sFlt-1/PlGF ratio with an area under curve (AUC) of 0.755 vs. 0.704, p = 0.002. The highest AUC values for PlGF and sFlt-1/PlGF ratio were seen for severe early-onset PE (0.901 and 0.883). Negative predictive values were high for all PE types, but positive predictive values were low. CONCLUSION: PlGF and sFlt-1/PlGF had good predictive value for PE at GW20-34 in a population-based unselected cohort, however with low positive predictive value.

Microfibrillar-Associated Protein 4: A Potential Biomarker for Screening for Liver Fibrosis in a Mixed Patient Cohort.

BACKGROUND AND AIMS: A method for assessment of liver fibrosis and cirrhosis without the need for a liver biopsy is desirable. Microfibrillar-associated protein 4 (MFAP4) is a suggested biomarker for identification of high-risk patients with severe fibrosis stages. This study aimed to examine associations between plasma MFAP4 (pMFAP4) and transient elastography or chronic hepatitis C virus infection in drug users and in a mixed patient cohort with increased risk of liver disease. Moreover, the study aimed to identify comorbidities that significantly influence pMFAP4. METHODS: pMFAP4 was measured in samples from 351 drug users attending treatment centres and from 248 acutely hospitalized medical patients with mixed diagnoses. Linear and logistic multivariate regression analyses were performed and nonparametric receiver operating characteristic-curves for cirrhosis were used to estimate cut-off points for pMFAP4. Univariate and subgroup analyses were performed using non-parametric methods. RESULTS: pMFAP4 increased significantly with liver fibrosis score. pMFAP4 was significantly associated with chronic viral infection in the drug users and with transient elastography in both cohorts. In the mixed patient cohort, pMFAP4 was significantly increased among patients with a previous diagnosis of liver disease or congestive heart failure compared to patients with other diagnoses. CONCLUSIONS: pMFAP4 has the potential to be used as an outreach-screening tool for liver fibrosis in drug users and in mixed medical patients. pMFAP4 level is positively associated with transient elastography, but additional studies are warranted to validate the possible use of pMFAP4 in larger cohorts and in combination with transient elastography.

Cell surface expression level variation between two common Human Leukocyte Antigen alleles, HLA-A2 and HLA-B8, is dependent on the structure of the C terminal part of the alpha 2 and the alpha 3 domains.

Constitutive cell surface expression of Human Leukocyte Antigen (HLA) class I antigens vary extremely from tissue to tissue and individual antigens may differ widely in expression levels. Down-regulation of class I expression is a known immune evasive mechanism used by cancer cells and viruses. Moreover, recent observations suggest that even minor differences in expression levels may influence the course of viral infections and the frequency of complications to stem cell transplantation. We have shown that some human multipotent stem cells have high expression of HLA-A while HLA-B is only weakly expressed, and demonstrate here that this is also the case for the human embryonic kidney cell line HEK293T. Using quantitative flow cytometry and quantitative polymerase chain reaction we found expression levels of endogenous HLA-A3 (median 71,204 molecules per cell) 9.2-fold higher than the expression of-B7 (P = 0.002). Transfection experiments with full-length HLA-A2 and -B8 encoding plasmids confirmed this (54,031 molecules per cell vs. 2,466, respectively, P = 0.001) independently of transcript levels suggesting a post-transcriptional regulation. Using chimeric constructs we found that the cytoplasmic tail and the transmembrane region had no impact on the differential cell surface expression. In contrast, ~65% of the difference could be mapped to the six C-terminal amino acids of the alpha 2 domain and the alpha 3 domain (amino acids 176-284), i.e. amino acids not previously shown to be of importance for differential expression levels of HLA class I molecules. We suggest that the differential cell surface expression of two common HLA-A and-B alleles is regulated by a post-translational mechanism that may involve hitherto unrecognized molecules.

The Odense Child Cohort: aims, design, and cohort profile.

BACKGROUND: The importance of the environment on the development of the fetus and infant throughout early life is increasingly recognised. To study such effects, biological samples and accurate data records are required. Based on multiple data collection from a healthy pregnant population, the Odense Childhood Cohort (OCC) study aims to provide new information about the environmental impact on child health by sequential follow-up to 18 years of age among children born between 2010 and 2012. METHODS: A total of 2874 of 6707 pregnancies (43%) were recruited between January 2010 and December 2012. Three hundred seventy-four have since left the study, leaving 2500 active families. The non-participants act as controls contributing data through local registries. Biological material, questionnaires, and registry data were compiled. Anthropometric data and other physical data were collected. RESULTS: Two thousand five hundred families actively participated in the study with 2549 children. Sixty-four per cent of the fathers and 60% and 58% of the mothers, respectively, donated a blood sample at 10 and 28 weeks of gestation. On average, 69% completed questionnaires, 78% of the children were regularly examined, and had a blood sample taken (46%). The participating pregnant women differed from the non-participants in several respects: age, body mass index, smoking, parity, education, and ethnicity. The infants were comparable with respect to gender and mode of delivery. CONCLUSIONS: The OCC provides material for in-depth analysis of environmental and genetic factors that are important for child health and disease. Registry data from non-participating women and infants are available which ensures a high degree of comparable data.

Infantile hemophagocytic lymphohistiocytosis in a case of chediak-higashi syndrome caused by a mutation in the LYST/CHS1 gene presenting with delayed umbilical cord detachment and diarrhea.

A 2-month-old female infant, born to consanguineous parents, presented with infections in skin and upper respiratory tract. She was notable for delayed umbilical cord detachment, partial albinism, and neurological irritability. Giant granules were present in white blood cells. The intracellular perforin content in CD8 T cells seems to correlate to the immune activation state of the patient with 82% and 8% perforin-containing CD8 T cells at active and nonactive hemophagocytic lymphohistiocytosis (HLH) disease, respectively. HLH was confirmed by hemophagocytosis in bone marrow and absent natural killer cell activity. The patient carried a homozygous G>A mutation in the 3' splice site of intron 24 of the LYST/CHS1 gene, leading to the use of an alternative YAG splice site located in exon 25, introducing a premature STOP codon (L2355fsX2370; NP_000072.2). The early-onset accelerated phase in this severe phenotype of Chediak-Higashi syndrome was probably induced by rotaviral infection. Interestingly, the intracellular perforin content in CD8 T cells seems to correlate to the immune activation state of the patient. Late separation of the umbilical cord in concordance with clinical symptoms should lead to evaluation of a possible neutrophil dysfunction including Chediak-Higashi syndrome before onset of HLH.

Diagnosis of preeclampsia with soluble Fms-like tyrosine kinase 1/placental growth factor ratio: an inter-assay comparison.

The angiogenic factor ratio soluble Fms-kinase 1 (sFlt-1)/placental growth factor (PlGF) is a novel diagnostic tool for preeclampsia. We compared the efficacy of the KRYPTOR (BRAHMS) automated assays for sFlt-1 and PlGF with the Elecsys (Roche) assays in a routine clinical setting. Preeclamptic women (n = 39) were included shortly after the time of diagnosis. Normotensive control pregnancies were matched by gestational age (n = 76). The KRYPTOR assays performed comparably or superior to Elecsys (sFlt-1/PlGF area under the curve 0.746 versus 0.735; P = .09; for non-obese 0.820 versus 0.805, P = .047). For early-onset preeclampsia, KRYPTOR area under the curve increased to 0.929 with a 100% specificity for preeclampsia at cut-off 85 and an 88.9% sensitivity for preeclampsia at cut-off 33. For women with preeclampsia and preterm delivery or Hemolysis, Elevated Liver enzymes, Low Platelet count (HELLP) syndrome, the KRYPTOR sFlt-1/PlGF ratio was manifold increased (P < .01). The sFlt-1/PlGF ratio proved especially useful in early-onset preeclampsia, preeclampsia with preterm delivery or HELLP, and among non-obese women.

Intracoronary injection of CD34-cells in chronic ischemic heart failure: 7 years follow-up of the DanCell study.

OBJECTIVES: Seven years ago, the DanCell study was carried out to test the hypothesis of improvement in left ventricular ejection fraction (LVEF) following repeated intracoronary injections of autologous bone marrow-derived stem cells (BMSCs) in patients suffering from chronic ischemic heart failure. In this post hoc analysis, the long-term effect of therapy is assessed. METHODS: 32 patients [mean age 61 (SD ± 9), 81% males] with systolic dysfunction (LVEF 33 ± 9%) received two repeated intracoronary infusions (4 months apart) of autologous BMSCs (1,533 ± 765 × 10(6) BMSCs including 23 ± 11 × 10(6) CD34(+) cells and 14 ± 7 × 10(6) CD133(+) cells). Patients were followed for 7 years and deaths were recorded. RESULTS: During follow-up, 10 patients died (31%). In univariate regression analysis, the total number of BMSCs, CD34(+) cell count and CD133(+) cell count did not significantly correlate with survival (hazard ratio: 0.999, 95% CI: 0.998-1.000, p = 0.24; hazard ratio: 0.94, 95% CI: 0.88-1.01, p = 0.10, and hazard ratio: 0.96, 95% CI: 0.87-1.07, p = 0.47, respectively). After adjustment for baseline variables in multivariate regression analysis, the CD34(+) cell count was significantly associated with survival (hazard ratio: 0.90, 95% CI: 0.82-1.00, p = 0.04). CONCLUSIONS: Intracoronary injections of a high number of CD34(+) cells may have a beneficial effect on chronic ischemic heart failure in terms of long-term survival.

Treatment of both native and deamidated gluten peptides with an endo-peptidase from Aspergillus niger prevents stimulation of gut-derived gluten-reactive T cells from either children or adults with celiac disease.

Celiac disease (CD) is characterized by an inappropriate immunological reaction against gluten driven by gluten-specific CD4+ T cells. We screened 25 proteases and tested 10 for their potential to degrade gluten in vitro. Five proteases were further tested for their ability to prevent the proliferative response by a gluten-specific CD4+ T cell clone and seven gluten-reactive T cell lines to protease-digested gluten peptides. A proline-specific endo-peptidase from Aspergillus niger (AnP2) was particularly efficient at diminishing proliferation after stimulation with cleaved antigen, and could completely block the response against both native and deamidated gluten peptides. We found that AnP2 was efficient down to a 1:64 protease:substrate ratio (w:w). When AnP2 was tested in assays using seven gluten-reactive T cell lines from individual CD patients (three adults and four children), the response to gluten was diminished in all cases. Our study indicates a therapeutic benefit of AnP2 to CD patients.

Enzyme-linked immunosorbent assay characterization of basal variation and heritability of systemic microfibrillar-associated protein 4.

BACKGROUND: Microfibrillar-associated protein 4 (MFAP4) is a systemic biomarker that is significantly elevated in samples from patients suffering from hepatic cirrhosis. The protein is generally localized to elastic fibers and other connective tissue fibers in the extracellular matrix (ECM), and variation in systemic MFAP4 (sMFAP4) has the potential to reflect diverse diseases with increased ECM turnover. Here, we aimed to validate an enzyme-linked immunosorbent assay (ELISA) for the measurement of sMFAP4 with an emphasis on the robustness of the assay. Moreover, we aimed to determine confounders influencing the basal sMFAP4 variability and the genetic contribution to the basal variation. METHODS: The sandwich ELISA was based on two monoclonal anti-MFAP4 antibodies and was optimized and calibrated with a standard of recombinant MFAP4. The importance of pre-analytical sample handling was evaluated regarding sample tube type, time, and temperature conditions. The mean value structure and variance structure was determined in a twin cohort including 1,417 Danish twins (age 18-67 years) by mixed-effect linear regression modeling. RESULTS: The practical working range of the sandwich ELISA was estimated to be 4-75 U/ml. The maximum intra- and inter-assay variation was estimated to be 8.7% and 6.6%, respectively. Sample handling and processing appeared to influence MFAP4 measurements only marginally. The average concentration of sMFAP4 in the serum was 18.9 ± 8.4 (SD) U/ml in the twin cohort (95% CI: 18.5-19.4, median sMFAP4 17.3 U/ml). The mean structure model was demonstrated to include waist-hip ratio, age, and cigarette smoking status in interactions with gender. A relatively low heritability of h(2) = 0.24 was found after applying a model including additive genetic factors and shared and non-shared environmental factors. CONCLUSIONS: The described ELISA provides robust measures of the liver fibrosis marker sMFAP4. The low heritability and the relatively limited basal variation suggest that increased sMFAP4 reflects disease-induced processes.